Development of Benedenia hoshinai (Monogenea) with Some Notes on its Occurrence on the Host

Abstract

A description is given of the development as well as some notes on the biology of Benedenia hoshinai OGAWA, 1984, a monogenean parasite of the Japanese striped kniifejaw Oplegnathus fasciatus (Japanese name: “Ishi-dai”). The oncomiracidium, 0.3-0.4mm long, attaches itself directly to the body surface and fins of the host, Adult worms are about 3.5mm long or over, being most abundant on the tail fin, dorsal soft fin rays and postero-dorsal side of the body. The hard parts (two pairs of hamuli and the supplementary pieces) show a clear relative growth to the parasite body length, and continue to grow even in adults. The number of worms on the host sharply decreased as they grew bigger than 1.5mm long, suggesting that most small worms detached themselves from the host before reaching that size.